<html xmlns="http://www.w3.org/1999/xhtml">
    <body onload="document.getElementById('f').setAttribute('class', 'e');">
        <math xmlns="http://www.w3.org/1998/Math/MathML">
            <mfenced id="f"/>
        </math>
        <p style="overflow: scroll; position: sticky;"></p>
    </body>
</html>
